An example of conventional steering wheels is disclosed in Japanese Patent Laid-open No. 193503/1993, which comprises an annular rim portion, a boss portion located inside the ring defined by the rim portion and attached to a steering shaft, and a plurality of spokes connecting the rim portion and the boss portion, wherein the two ends of the core metal of each spoke are respectively enveloped in a die-cast metal by means of die casting and connected to the boss-core metal of the boss portion and the rim-core metal of the rim portion. However, the lower portion of the boss-side end of each spoke-core metal is not covered by the die-cast metal. The exposed part faces downward. With the configuration as above, in the event where a shock is delivered from above to the rim portion, the spoke-core metals bend, in a peeling off manner from the die-cast metal, thereby absorbing the shock.
However, the conventional configuration described above, wherein the lower part of the end of each spoke-core metal adjacent to the boss portion is exposed from the die-cast metal, causes a decrease in the resonance frequency of a steering wheel. This makes it difficult to reduce vibration of the steering wheel which results from vibration of the engine or other sources. In other words, the conventional configuration presents a problem in that it is difficult to make a steering wheel more comfortable to operate.
In order to prevent the above problems, an object of the present invention is to provide a steering wheel which has superior shock absorbing characteristics and is comfortable to operate due to reduced vibration.